1. Technical Field
The present disclosure generally relates to computing or information technology (IT) data centers. More particularly, the present disclosure relates to structures, systems and methods for installing heat exchangers in IT data centers.
2. Background of Related Art
Over the past several years, computer equipment manufacturers have expanded the data collection and storage capabilities of their servers. The expansion of server capabilities has led to an increase in total power consumption and total heat output per server and per server rack assembly in data centers. It has also led to an increase in power and temperature control requirements for computer data collection and storage. As a result, the data collection and storage industry has sought and is seeking new, innovative equipment, systems, and design strategies to handle the tremendous and continued growth in capacity of computer data collection and storage.
Cooling systems for computer server racks have been struggling to keep pace with the ability to cool ever increasing computer server heat loads in data centers. The increase of computer server heat loads (measured in kilowatts (kW)) has required that more space be allotted for the cooling infrastructure within the data rooms or that the cooling systems are concentrated at the heat source, i.e., the computer server racks. Recently, cooling systems have been designed to concentrate the cooling at the computer server racks. These cooling systems include rear-door heat exchangers and rack-top coolers.
Certain cooling system designs have incorporated de-ionized water while others use R-134a (i.e., 1,1,1,2-Tetrafluoroethane) refrigerant in a mostly liquid state. The latest designs are limited in their ability to be scaled to cooling requirements of increasingly high density data centers. The output capacity of rear-door exchangers is limited to the physical size of the computer rack exterior perimeter and the amount of fluid (measured in gallons per minute (gpm)) that can be applied to a rear-door exchanger without excessive pressure drops. The rear-door exchangers can produce up to approximately 12-16 kW of concentrated cooling to computer server racks. The overhead rack coolers can produce up to 20 kW of cooling output using R-134a refrigerant liquid. This is based on a cooling system design that does not change the state of the refrigerant. Therefore, the total capacity is limited to the physical size of the coils as well as the size of the enclosure for the computer server racks. This equates to approximately 41,000 to approximately 55,000 BTUs per hour (about 12 KW to about 16.1 KW) of total heat rejection capabilities per rack assembly.
Some computer servers can now produce outputs in excess of 35 kW similar to the IBM Blue Jean Server. The rear-door heat exchangers and other similar cooling products on the market cannot handle the cooling requirements of these high-density computer servers.
Many existing data centers have been constructed with in-row rack cooling systems and integral hot and cold aisle containment. These data centers, however, waste a significant amount of space. Also, it is difficult to increase the cooling capacity of the in-row rack cooling systems when servers are added to the server racks or existing servers are replaced with servers requiring more cooling capacity. Furthermore, it is difficult for many existing data centers to upgrade their cooling systems to comply with future government regulations that require reductions in energy consumption. Thus, the data center industry has been seeking energy efficient modular cooling solutions for new and existing white space in data centers, as well as “just-in-time” and modular cooling expansion capabilities both at the server level as well as at the overall rack level.